I am building an application that maintains an available cash balance for services purchased, funded by credit card or money order. Naturally, as a small startup, performance isn't much of an issue, since the volume won't be there in the beginning.
That said, my budget is tiny READ: open source for now. I would be a fool to use the traditional Z mainframe; oracle for that matter, so I am debating between innodb or myisam engine for mysql.
For most of my projects, I choose innodb. Could such be a viable option, for, say the first hypothetical 100K customers? Or myisam? Is table locking recommended for financial transactions?